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Simplify venv docs.
Now that venv is in stdlib, we can just recommend it instead of suggesting a bunch of workarounds for virtualenv on OSX. In the general venv docs, rework the first paragraph, which was phrased a bit awkwardly; move vext above virtualenv because the former also works in venvs (which again should be preferred).
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‎doc/faq/osx_framework.rst‎

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.. contents::
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:backlinks: none
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.. highlight:: bash
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.. _osxframework_introduction:
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Introduction
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============
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On OSX, two different types of Python builds exist: a regular build and a
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framework build. In order to interact correctly with OSX through the native
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GUI frameworks you need a framework build of Python. At the time of writing
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GUI frameworks, you need a framework build of Python. At the time of writing
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the ``macosx`` and ``WXAgg`` backends require a framework build to function
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correctly. This can result in issues for a Python installation not build as a
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framework and may also happen in virtual envs and when using (Ana)Conda. From
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correctly. This can result in issues for a Python installation not build as a
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framework and may also happen in virtual envs and when using (Ana)conda. From
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Matplotlib 1.5 onwards, both backends check that a framework build is available
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and fail if a non framework build is found.
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Without this check a partially functional figure is created.
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Among the issues with it is that it is produced in the background and
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cannot be put in front of any other window. Several solutions and work
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arounds exist see below.
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and fail if a non framework build is found. (Without this check a partially
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functional figure is created. In particular, it is produced in the background
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and cannot be put in front of any other window.)
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Short version
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=============
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VirtualEnv
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virtualenv
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----------
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If you are on Python 3, use
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`venv <https://docs.python.org/3/library/venv.html>`_
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instead of `virtualenv <https://virtualenv.pypa.io/en/latest/>`_::
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python -m venv my-virtualenv
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source my-virtualenv/bin/activate
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In a virtualenv_, a non-framework build is used even when the environment is
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created from a framework build (`virtualenv bug #54`_, `virtualenv bug #609`_).
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Otherwise you will need one of the workarounds below.
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The solution is to not use virtualenv, but instead the stdlib's venv_, which
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provides similar functionality but without exhibiting this issue.
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Pyenv
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-----
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If you are using pyenv and virtualenv you can enable your python version to be installed as a framework::
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If you absolutely need to use virtualenv rather than venv, then from within
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the environment you can set the ``PYTHONHOME`` environment variable to
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``$VIRTUAL_ENV``, then invoke Python using the full path to the framework build
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(typically ``/usr/local/bin/python``).
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PYTHON_CONFIGURE_OPTS="--enable-framework" pyenv install x.x.x
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.. _virtualenv: https://virtualenv.pypa.io/
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.. _virtualenv bug #54: https://github.com/pypa/virtualenv/issues/54
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.. _virtualenv bug #609: https://github.com/pypa/virtualenv/issues/609
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.. _venv: https://docs.python.org/3/library/venv.html
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Conda
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conda
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-----
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The default python provided in (Ana)Conda is not a framework
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build. However, the Conda developers have made it easy to install
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a framework build in both the main environment and in Conda envs.
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To use this install python.app ``conda install python.app`` and
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use ``pythonw`` rather than ``python``
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Long version
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============
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Unfortunately virtualenv creates a non
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framework build even if created from a framework build of Python.
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As documented above you can use venv as an alternative on Python 3.
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The issue has been reported on the virtualenv bug tracker `here
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<https://github.com/pypa/virtualenv/issues/54>`__ and `here
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<https://github.com/pypa/virtualenv/issues/609>`__
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Until this is fixed, one of the following workarounds can be used:
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``PYTHONHOME`` Function
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-----------------------
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The best known work around is to use the non
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virtualenv python along with the PYTHONHOME environment variable.
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This can be done by defining a function in your ``.bashrc`` using ::
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function frameworkpython {
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if [[ ! -z "$VIRTUAL_ENV" ]]; then
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PYTHONHOME=$VIRTUAL_ENV /usr/local/bin/python "$@"
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else
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/usr/local/bin/python "$@"
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fi
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}
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This function can then be used in all of your virtualenvs without having to
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fix every single one of them.
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With this in place you can run ``frameworkpython`` to get an interactive
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framework build within the virtualenv. To run a script you can do
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``frameworkpython test.py`` where ``test.py`` is a script that requires a
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framework build. To run an interactive ``IPython`` session with the framework
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build within the virtual environment you can do ``frameworkpython -m IPython``
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``PYTHONHOME`` and Jupyter
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^^^^^^^^^^^^^^^^^^^^^^^^^^
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This approach can be followed even if using `Jupyter <https://jupyter.org/>`_
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notebooks: you just need to setup a kernel with the suitable ``PYTHONHOME``
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definition. The `jupyter-virtualenv-osx <https://github.com/mapio/jupyter-virtualenv-osx>`_
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script automates the creation of such a kernel.
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``PYTHONHOME`` Script
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^^^^^^^^^^^^^^^^^^^^^
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An alternative work around borrowed from the `WX wiki
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<https://wiki.wxpython.org/wxPythonVirtualenvOnMac>`_, is to use the non
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virtualenv python along with the PYTHONHOME environment variable. This can be
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implemented in a script as below. To use this modify ``PYVER`` and
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``PATHTOPYTHON`` and put the script in the virtualenv bin directory i.e.
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``PATHTOVENV/bin/frameworkpython`` ::
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#!/bin/bash
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# what real Python executable to use
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PYVER=2.7
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PATHTOPYTHON=/usr/local/bin/
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PYTHON=${PATHTOPYTHON}python${PYVER}
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# find the root of the virtualenv, it should be the parent of the dir this script is in
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ENV=`$PYTHON -c "import os; print(os.path.abspath(os.path.join(os.path.dirname(\"$0\"), '..')))"`
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# now run Python with the virtualenv set as Python's HOME
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export PYTHONHOME=$ENV
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exec $PYTHON "$@"
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With this in place you can run ``frameworkpython`` as above but will need to add this script
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to every virtualenv
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PythonW Compiler
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----------------
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In addition
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`virtualenv-pythonw-osx <https://github.com/gldnspud/virtualenv-pythonw-osx>`_
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provides an alternative workaround which may be used to solve the issue.
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The default python provided in (Ana)conda is not a framework build. However,
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a framework build can easily be installed, both in the main environment and
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in conda envs: install python.app (``conda install python.app``) and use
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``pythonw`` rather than ``python``

‎doc/faq/virtualenv_faq.rst‎

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Working with Matplotlib in Virtual environments
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***********************************************
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When running Matplotlib in a `virtual environment
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<https://virtualenv.pypa.io/en/latest/>`_ you may discover a few issues.
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Matplotlib itself has no issue with virtual environments. However, some of
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the external GUI frameworks that Matplotlib uses for interactive figures may
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be tricky to install in a virtual environment. Everything below assumes some
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familiarity with the Matplotlib backends as found in :ref:`What is a backend?
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<what-is-a-backend>`.
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While Matplotlib itself runs fine in a `virtual environment
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<https://docs.python.org/3/library/venv.html>`_ (venv), some of the GUI
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frameworks that Matplotlib uses for interactive figures are tricky to install
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in a venv. Everything below assumes some familiarity with the Matplotlib
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backends as found in :ref:`What is a backend? <what-is-a-backend>`.
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If you only use the IPython and Jupyter Notebook's ``inline`` and ``notebook``
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backends, or non-interactive backends, you should not have any issues and can
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============= ========================== =================================
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GUI framework pip-installable? conda or conda-forge-installable?
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============= ========================== =================================
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PyQt5 on Python>=3.5 yes
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PyQt5 yes yes
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------------- -------------------------- ---------------------------------
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PyQt4 PySide: on Windows and OSX yes
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------------- -------------------------- ---------------------------------
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PyGObject no on Linux
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------------- -------------------------- ---------------------------------
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PyGTK no no
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------------- -------------------------- ---------------------------------
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wxPython yes [#]_ yes
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============= ========================== =================================
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.. [#] OSX and Windows wheels available on PyPI. Linux wheels available but
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not on PyPI, see https://wxpython.org/pages/downloads/.
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In other cases, you need to install the package in the global (system)
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site-packages, and somehow make it available from within the virtual
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environment. This can be achieved by any of the following methods (in all
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cases, the system-wide Python and the virtualenv Python must be of the same
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version):
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- Using ``virtualenv``\'s ``--system-site-packages`` option when creating
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an environment adds all system-wide packages to the virtual environment.
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However, this breaks the isolation between the virtual environment and the
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system install. Among other issues it results in hard to debug problems
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with system packages shadowing the environment packages. If you use
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`virtualenvwrapper <https://virtualenvwrapper.readthedocs.io/>`_, this can be
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toggled with the ``toggleglobalsitepackages`` command.
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For cases where the framework is not installable in a venv, it needs to be
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install the package in the global (system) site-packages, and then made
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available from within the venv. This can be achieved by either of the
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following methods (in all cases, the system-wide Python and the venv Python
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must be of the same version):
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- `vext <https://pypi.python.org/pypi/vext>`_ allows controlled access
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from within the virtualenv to specific system-wide packages without the
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It is recommended to use ``vext>=0.7.0`` as earlier versions misconfigure the
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logging system.
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- When using `virtualenv <https://virtualenv.pypa.io/>` (rather than the
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stdlib's ``venv``), using the ``--system-site-packages`` option when creating
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an environment adds all system-wide packages to the virtual environment.
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However, this breaks the isolation between the virtual environment and the
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system install. Among other issues it results in hard to debug problems
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with system packages shadowing the environment packages. If you use
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`virtualenvwrapper <https://virtualenvwrapper.readthedocs.io/>`_, this can be
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toggled with the ``toggleglobalsitepackages`` command.
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If you are using Matplotlib on OSX, you may also want to consider the
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:ref:`OSX framework FAQ <osxframework-faq>`.

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